Conventional control systems for automotive vehicles commonly involve means for sensing engine parameters, and a controller for reading those sensed values and for issuing control commands to the engine in accord with those sensed values. The quality of the control is constrained by, among other things, the integrity of the sensed values, i.e. the proximity of the value the sensing means provides the controller to the actual present value of the parameter.
Generally, the sensing means have some delay time associated with their response, such that by the time the sensed signal becomes available to the engine controller, the parameter may have undergone a significant change in value resulting in substantial error between the sensed value and the actual present value of the parameter, which may erode the precision of the engine control.
Prior attempts to reduce the effect of sensor lag have included the use of high speed sensors, which provide parameter information to the system controller with reduced transmission delay. This solution usually involves increased cost, and cannot completely eliminate the delay.
Parameter sensing systems have also proposed the use of future value estimating means for estimating the value of a sensed parameter at some future time, such as when an actuator is set into motion. These systems do not compensate for potentially substantial delays in the sensing means itself, and therefore provide the system controller with obsolete parameter information. Additionally, many of these systems use strictly linear approximations of the future value of the parameter, ignoring non-linear peculiarities in the parameter trajectory. Accordingly, such estimating approaches may limit the accuracy of the engine control.
Consequently, it would be desirable to provide the controller with the present value of relevant control parameters by eliminating or reducing sensor lag, without increasing system cost significantly, and without ignoring non-linearities in the parameter trajectory.